STMicroelectronics M74HCT32B1R

Overview

M74HCT32B1R from STMicroelectronics is a high-speed CMOS quad 2-input OR gate in 14-pin DIP package, designed for TTL/NMOS interface compatibility with 13 ns typical propagation delay (VCC = 4.5 V), 4 mA minimum output drive, and 1 µA max quiescent ICC at 25°C. It operates across -55°C to +125°C and is used in industrial control logic, bus arbitration, and level-shifting combinational circuits.

For engineers reviewing the M74HCT32B1R datasheet, M74HCT32B1R pinout, M74HCT32B1R application, or M74HCT32B1R equivalent, key selection criteria include input threshold compatibility (VIH ≥ 2.0 V, VIL ≤ 0.8 V), symmetrical output impedance (|IOH| = IOL ≥ 4 mA), wide temperature range support, and direct 74-series functional replacement capability.

Technical Context

The M74HCT32B1R implements four independent OR gates using silicon gate C2MOS technology with buffered outputs, enabling high noise immunity and stable switching. Its two-stage internal architecture ensures balanced tPLH ≈ tPHL propagation delays and symmetrical output drive strength under load.

It features input protection against ESD and transient overvoltage, supports 4.5–5.5 V supply operation, and maintains TTL-compatible input thresholds (VIH min = 2.0 V, VIL max = 0.8 V) while delivering CMOS-level power efficiency and speed.

Key Specifications

Pinout & Package

Package: Plastic DIP-14 (Dual In-line Package, 14-pin, 0.3" width, through-hole mount).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input OR gate applications.

Compared with SN74HCT32N and 74HCT32D, the M74HCT32B1R offers identical logic performance and temperature range but provides through-hole DIP-14 mechanical reliability for manual assembly, field repair, and thermal cycling resilience in non-SMT industrial modules.

Availability

M74HCT32B1R is available at Aetrix Electronics and suitable for industrial control systems, automotive body electronics, legacy interface adapters, and test equipment requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for M74HCT32B1R includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management solutions with broad analog, digital, and mixed-signal portfolio coverage.

The M74HCT32B1R belongs to ST's legacy HCT logic family, engineered for seamless interoperability between TTL, NMOS, and CMOS systems while maintaining low power consumption and robust industrial-grade reliability.

FAQ

What is the maximum operating frequency for reliable OR-gate operation?

The M74HCT32B1R does not specify a maximum clock frequency, as it is a combinational logic device. However, with 13 ns typical propagation delay and 26 ns worst-case (–55°C to +125°C), it supports stable operation in systems where input signal transitions occur no faster than ~20 MHz for clean setup/hold margins in synchronous designs.

Can this part be used with a 3.3 V supply?

No. The M74HCT32B1R is specified only for 4.5 V to 5.5 V operation. At 3.3 V, VIH and VIL thresholds become undefined, output drive degrades below specification, and DC parameters such as VOH/VOL fall outside guaranteed limits - use 74HCT32 variants rated for 3.3 V (e.g., 74AHCT32) instead.

Does it require external pull-up or pull-down resistors on unused inputs?

Yes. Unused inputs must be tied to VCC or GND to prevent floating states that cause increased ICC, noise susceptibility, and potential oscillation. ST recommends connecting unused inputs directly to VCC (for OR gates, this forces output high) or GND (output follows other input), never left open.

Is the DIP-14 package RoHS compliant?

Yes. The M74HCT32B1R (order code suffix 'B1R') is manufactured in a lead-free, RoHS-compliant plastic DIP-14 package per STMicroelectronics' 2006 transition program, with exemption 7a (lead in high-melting-temperature solder) not applied - fully compliant with Directive 2011/65/EU.